(a) Field of the Invention
The invention relates to a steering structure of a bicycle or scooter, more particularly to an improved structure for a steering spindle securing device of a bicycle or scooter.
(b) Description of the Prior Art
In the prior art, the steering mechanism of a conventional scooter in general follows the design of steering mechanisms of bicycles. The structure thereof generally includes a steering spindle 60. Referring to FIG. 1, the outer side of the body of the steering spindle 60 has an outer thread, the bottom end having a wheel frame 62 for mounting pivotally a front wheel. The steering spindle 60 is accommodated within a spindle sleeve 70. The spindle sleeve 70 has upper and lower ends provided with two bearings 71. The outer ring 711 of the two bearings 71 are in tight fit with the spindle sleeve 70, while the inner ring 712 is in tight fit with the spindle 60. A press element 81 is threadedly coupled to the outer thread 61 of the steering spindle 60, and has a bottom end having a generally wedge-shaped press portion 811 for vertically pressing against the inner ring 712 of the bearing 71. An adjusting nut 82 is threadedly coupled to the outer thread 61 of the steering spindle 60 and located above the press element 81. By turning the adjusting nut 82 to adjust the size of the pressure exerted by the press element 81 on the inner ring 712 of the bearing 71, smooth rotation of the spindle 60 can be controlled. Besides, the press element 81 can be prevented from rotation relative to the outer thread 61 of the steering spindle 60. Finally, a control rod 90 is connected to the outer end of the spindle 60, and a positioning element is used to secure the control rod 90 and the spindle 60 to thereby enable the user to turn the control rod 90 for control steering of the scooter.
In the above steering structure, during assembly of the components, since the press element 81 and the adjusting nut 82 are threadedly coupled to the outer thread 61 of the spindle 60 and since the outer thread 61 of the spindle 60 is formed by the use of a special lathe, the manufacturing process is troublesome and costs are high.